Proper use of subspecies categories

One of the things you’ll notice while entering eBird data is that we include the option of entering subspecies for a small number of birds. Categories like “Fox Sparrow (Red)” and “Red-tailed Hawk (Eastern)” are offered in addition to “Fox Sparrow” and “Red-tailed Hawk,” for example. But other subspecies, such as “Herring Gull (American)” or “Dark-eyed Junco (Red-backed),” are not. While it may appear there is no rhyme or reason to all this, this is actually something we have thought through carefully.  Our selections were designed to inform users of our recommended proper uses of subspecies. In this blogpost, we would like to showcase a number of examples of subspecies currently allowed in Michigan, with notes on our recommended uses. Our overarching goal is to implore users to only claim identifications that are based on field marks they observed in the field, not on expectation/range.

To take one example, even though “Yellow Warbler (Northern)” is the only subspecies of Yellow Warbler which has ever occurred in Michigan, we do not include this category in the Michigan filters, arguing that it doesn’t add any information to the eBird dataset here. “Yellow Warbler” data from Michigan can already be assumed to be of the Northern subspecies, so records entered under both titles are interchangeable. So, we just have “Yellow Warbler” in the filters, which also creates less clutter to scroll through during data entry. Of course, if you prefer to enter Yellow Warblers as Northerns, you can click “add species” and do this. Do note, however, that these observations will flag.

So, if you don’t observe the field marks necessary to identify a species down to the subspecies level, we ask that you use the general category. But, if you carefully checked to make sure the bird actually possessed the critical field marks of the subspecies claimed, and you carefully counted all the individuals that did, then go ahead and use the subspecies category for those individuals. Here are some detailed notes about how to eBird some of our most commonly-used categories.

Example 1: Dark-eyed Junco

Filter options:

Dark-eyed Junco
Dark-eyed Junco (Oregon)
Dark-eyed Junco (Slate-colored)
Dark-eyed Junco (Slate-colored/Cassiar)
Dark-eyed Junco (Cassiar)

This extremely variable species has three forms which occur annually in Michigan: Slate-colored (the common, numerous form), Oregon (a few annually), and Cassiar (complicated, but perhaps 1-3 well-documented birds annually). Of these, we only allow Slate-colored (nearly as many as Dark-eyed Junco) and Slate-colored/Cassiar (only one bird during winter) to be claimed without the observation flagging. Slate-colored/Cassiar is intended to capture those unusually orangish or buffy birds which often stand out among your wintering Slate-coloreds, but cannot be identified easily. However, since Oregon and Cassiar represent very difficult identification quagmires and are genuinely very uncommon, all observations will flag.

In a nutshell, if you check carefully and your junco(s) is/are clearly Slate-colored, then use “Dark-eyed Junco (Slate-colored).” If you hear a singing junco, or see one but don’t check carefully, then it should be entered as “Dark-eyed Junco.” If you observe an unusually buffy junco, but one that is not clearly an Oregon or Cassiar, then use “Dark-eyed Junco (Slate-colored/Cassiar)”. If you feel confident you’ve seen an Oregon or Cassiar Junco, please include extensive notes and attempt to get photos, if at all possible.

Example 2: Fox Sparrow

Filter options:

Fox Sparrow
Fox Sparrow (Red)

Only one form has been recorded in Michigan: Fox Sparrow (Red). None of the western races have been recorded in Michigan and, thus, are excluded from the filters.

If you see a Fox Sparrow well enough to rule out the darker-backed forms of the Rockies and the west coast, enter it as “Fox Sparrow (Red).” If not, please use “Fox Sparrow.”

Example 3: Herring Gull

Filter options:

Herring Gull

In this case, only one subspecies is known to occur in Michigan: American (smithsonianus). The European subspecies argenteus (and possibly, argentatus) is known from the Atlantic coast of North America, but its true occurrence is clouded by the difficulty of positively identifying it. In any event, in Michigan, our “Herring Gull” data can already be used interchangeably with “Herring Gull (American),” so we only include “Herring Gull” in the filter. If you take the time to identify birds to subspecies, feel free to add “Herring Gull (American)” to your checklist, but again, it will flag and reviewers will ask how you determined them to be “American.”

Example 4: Northern Flicker

Filter options:

Northern Flicker
Northern Flicker (Yellow-shafted)
Northern Flicker (intergrade)

Currently, the only common flicker in Michigan is Yellow-shafted. Red-shafted is accidental, based on a single state record, and is excluded from the filter. However, the status of intergrade birds is less clear. Birds with mixed color flight feathers are recorded annually or nearly annually in Michigan, but whether these are true Great Plains-originating hybrids, or Yellow-shafteds with pigmentation issues, is not clear. In any event, heard only or distant flickers should be eBirded as “Northern Flicker,” while birds with all yellow remiges and facial characteristics eliminating Red-shafted, should be eBirded as “Northern Flicker (Yellow-shafted).”

Side note: all filters allow an additional category for heard-only woodpecker drumming, “woodpecker sp.” Though drumming by Yellow-bellied Sapsucker and Pileated Woodpecker are readily identifiable the drums of other species are much more difficult to identify and should only be eBirded if the bird is seen.

Example 5: Green-winged Teal

Filter options:

Green-winged Teal
Green-winged Teal (American)

The only regularly-occurring subspecies of Green-winged Teal is American (carolinensis). There is only one record of the Eurasian form (crecca), so this option is excluded from the filters. An additional complication comes with the fact that intergrades (ie. carolinensis x crecca) are at least as common as pure crecca in the interior of North America; for example, see this bird from Kent County in spring 2014. These are also accidental and thus not in the filter.

For most sightings, our recommendation for well-seen males is to use “Green-winged Teal (American),” as long as the vertical lateral breast bar is present and the horizontal scapular bar of Eurasian is totally absent. However, all female-type birds (including young males and eclipse males) should be eBirded as “Green-winged Teal,” since it is not possible to separate these birds definitively from crecca or intergrades. If you don’t care to take the time to check each drake, then eBird them all as “Green-winged Teal.” We just don’t recommend using “Green-winged Teal (American),” unless it refers to a breeding-plumaged (ie. basic) male.

Example 6: Red-tailed Hawk

Filter options:

Red-tailed Hawk
Red-tailed Hawk (Eastern)
Red-tailed Hawk (Western)
Red-tailed Hawk (Northern)

Red-tailed Hawks can be very difficult to identify to subspecies. This may be the only species in Michigan with multiple regularly-occurring subspecies. Michigan has three: Eastern (borealis) is resident and partially migratory; Western (calurus) is rare, but annual, during migration and winter; and Northern (albieticola) is poorly-known but occurs during migration and winter. Any claims of Western or Northern will flag. The identification criteria for Northern are very poorly recognized by most birders, and the first official detailed treatise by Jerry Liguori and Brian Sullivan of this Canadian- and Alaskan-nesting form was only recently published in 2004. We strongly recommend all birders read this article in detail before claiming any Northern in Michigan.

The vast majority of Red-tailed Hawks in Michigan (and the only ones in summer) are Easterns. During migration and winter one must also consider the relatively rare options of Western and Northern. Nesting or territorial pairs can be assumed to be Eastern on behavior, but the plumage of birds during migration and winter should be checked, especially throat color, breast band, and tail barring (see Liguori and Sullivan 2014). So, for the majority of relaxed birding outings, we recommend using only “Red-tailed Hawk.” But, if you make an effort to assess plumage and/or territorial behaviors, feel free to eBird individuals to the appropriate subspecies category.

Example 7: Cackling Goose

Filter options:

Cackling Goose
Cackling Goose (Richardson’s)

As outlined in our detailed blogpost, identification of this complex can be extremely tricky. The only subspecies of Cackling Goose known from Michigan is Richardson’s (hutchinsii), so all reports are assumed to be this subspecies.

If a Cackling Goose is seen well enough to eliminate taverneri (perhaps a remote possibility to occur in Michigan) and the Alaskan/west coast specialty subspecies (minima and leucopareia), then use “Cackling Goose (Richardson’s).” If not, use Cackling Goose. And as always, be prepared for “Cackling-ish Geese,” as outlined by David Sibley in December 2014 and us in our blogpost. These birds appear smaller than the Canadas they are with, but are not countable as Cackling Geese. These should always be eBirded as Cackling/Canada Goose.

Example 8: Yellow-rumped Warbler

Filter Options:

Yellow-rumped Warbler
Yellow-rumped Warbler (Myrtle)
Yellow-rumped Warbler (Audubon’s)

The only regularly-occurring subspecies of Yellow-rumped Warbler in Michigan is Myrtle (coronota), which breeds in large numbers north of the tension line, and winters in very small numbers to its south. The western subspecies auduboni is accidental. Furthermore, these two subspecies hybridize (technically: intergade) in western Canada on the nesting grounds. See the eBird map for hybrids and study the photos (click “Explore Rich Media”) to get an idea of the variation and difficult identification of these birds. No Michigan records of known intergrades exist, but this Audubon’s-like bird from Lowell in winter 2007/2008 may have been a hybrid.

So, if you study a Yellow-rumped well enough to eliminate Audubon’s and an intergrade, use “Yellow-rumped Warbler (Myrtle),” but if not, use “Yellow-rumped Warbler.” Any presumed Audubon’s or intergrade should be added to the checklist with detailed notes (and photos, if possible).

Example 9: Palm Warbler

Filter options:

Palm Warbler
Palm Warbler (Western)

Palm Warblers are common migrants throughout Michigan. They nest in our northern bogs and dry coniferous forests, but do not winter. The Western subspecies (palmarum) is the only regularly-occurring subspecies here, however the Yellow, eastern, subspecies hypochrysea has occurred a handful of times, but it still accidental.

In order to eBird a Palm Warbler as Western, one should check to confirm that the lower breast and belly are white and the breast and undertail coverts are yellow. In basic/juvenal plumage focus on the color of the back, rump, and wing covert edgings. Otherwise, all Palm Warblers (especially heard only) should be eBirded as “Palm Warbler.”

Example 10: White-crowned Sparrow

Filter options:

White-crowned Sparrow
White-crowned Sparrow (Eastern)
White-crowned Sparrow (Gambel’s)

Eastern White-crowned Sparrow (leucophrys) is the only common subspecies in Michigan. It has dark lores, a pinkish bill, and brown lateral crown stripes. The western form gambelli (Gambel’s), annual in small numbers in Michigan, has pale lores, a pale orange and yellow “candy corn” bill, and rufous lateral crown stripes. However, identification in this complex is complicated by intermediate birds not perfectly matching either category. So all Gambel’s will flag. See this helpful summary of birds banded by Julie Craves of River Rouge Bird Observatory for help sorting through the variation.

Well-studied birds matching leucophrys can be eBirded as such. However, heard only birds, or those not studied carefully, should be eBirded as “White-crowned Sparrow.” We do not recommend using “White-crowned Sparrow (Dark-lored)” in Michigan, as this category includes both leucophrys and the western Mountain subspecies oriantha, which has not occurred (or expected) in Michigan.

Summary
In order to de-clutter the Michigan eBird filters, we have eliminated subspecies which are accidental. Those that are casual or regular are included. However, tricky identifications are also not allowed without flagging. We implore all users to check birds carefully for subspecies traits, and never to claim subspecies based on expectation or range, even when only one subspecies occurs. Claim only those individuals that were carefully checked, and let the rest go under the broad category.

We hope this blogpost helps you to better understand how and when to use the various subspecies categories offered in Michigan! Enjoy the waves of neotropical migrants currently arriving…

Team eBird Michigan
Adam, Caleb, and Brian

 

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